Fabrication of remote controllable devices with multistage responsiveness based on a NIR light-induced shape memory ionomer containing various bridge ions

Near-infrared (NIR) light responsive devices have attracted extensive scientific attention due to their wide range of applications in biomedical devices, soft robotics and wearable electronics. However, the easy fabrication of these devices and the corresponding shape memory materials is still a challenge. Herein, we synthesized a series of novel NIR-induced shape memory ionomers with multistage responsiveness using commercialized polymers as the framework and various metal ions as cross-linked junctions, which exhibit a high shape recovery ratio of over 93%. The light-induced shape memory properties of the ionomer can be freely tailored by merely adjusting the species and content of metal ions due to the specific photothermal effect of each ion. Moreover, the dynamic ionic cross-linked interaction also causes light-induced plasticity, leading to repeatable programming of these ionomers to new permanent shapes without sacrificing their shape memory properties. The combination of these ionomers containing different bridge ions is able to achieve light-induced multistage shape modulation, which was further used to fabricate several devices, such as light-operated actuators and switches, demonstrating their versatile application potential in various fields.